I just got my Rebel XT and have been cruising these forums for some advice on upgrading the "kit lens" that came with the camera. I prefer to get one"walk around" lens instead of a two lens kit. I was looking around and found this lens:

Canon EF 28-105mm 1:3.5-4.5 USM

Seems to be very popular and rather inexpensive ($250ish). Would this be a decent upgrade from the kit lens? My needs are most "family" stuff with soccer, trips, birthdays, etc. The kit lens doee not seem to have enough "zoom" for me. I had a point and shoot Lumix w/12x zoom which I enjoyed. I know that this will not zoom in as far but this seems to be a good balance between optical quality and zoom. Any other sugestions? I've seen some Sigma and Tamron lenses but am not sure of the optic quality.

One of the 18-200s would probably best suit your needs. Canon's cheaper lenses are not very good value as many third parties have newer and better models and these are generally also cheaper.
I have to ask though, if you only want to have one lens why did you buy an SLR?

One of the 18-200s would probably best suit your needs. Canon's cheaper lenses are not very good value as many third parties have newer and better models and these are generally also cheaper.
I have to ask though, if you only want to have one lens why did you buy an SLR?

Could you be specific as to what 18-200 lens you are referring to?

Also, as stated, I am new to DSLR. I can always get into buying more lenses later. For now, I would like to have one decent lens that I can get more familiar with the camera.

The Canon 17-85 IS lens is an excellent upgrade. After the conversion factor of 1.6x, it is the equivalent of a 27-136 mm lens on a35 mm. camera. It is worth the price. You can sell your old lens on e-bay.

I just got my Rebel XT and have been cruising these forums for some advice on upgrading the "kit lens" that came with the camera. I prefer to get one"walk around" lens instead of a two lens kit. I was looking around and found this lens:

Canon EF 28-105mm 1:3.5-4.5 USM

Seems to be very popular and rather inexpensive ($250ish). Would this be a decent upgrade from the kit lens? My needs are most "family" stuff with soccer, trips, birthdays, etc. The kit lens doee not seem to have enough "zoom" for me. I had a point and shoot Lumix w/12x zoom which I enjoyed. I know that this will not zoom in as far but this seems to be a good balance between optical quality and zoom. Any other sugestions? I've seen some Sigma and Tamron lenses but am not sure of the optic quality.

My friend, you bought the wrong camera. The lens you want is a Nikon 18-200mm VR. Problem with a 28-anything lens as an all-purpose lens is that it is not wide enough on your camera. That is why the kit is 18-55, and the popular upgrade is 17-85mm. I have the 17-85mm, and it is fine. Too short for soccer, though. That's where the 18-200 would be handy. Tamron and Sigma both make an 18-200mm lens in a Canon mount, but neither have image stabilization like the Nikon. The Canon 17-85 has IS, but it is not long enough.

Oh yes, the other advantage of the Canon 17-85 is that it will get you lots of practice in fixing chromatic aberration in Photoshop! What a pain that lens is shooting high contrast--mountains, buildings, etc.!!!

Oh yes, the other advantage of the Canon 17-85 is that it will get you lots of practice in fixing chromatic aberration in Photoshop! What a pain that lens is shooting high contrast--mountains, buildings, etc.!!!

What you need is DXO Optics, it's a software upgrade for all your lenses - you won't need an L!

Seriously though, even without DXO I have never had a shot with significant CA from my 17-85, vignetting and distortion yes, but CA no. Perhaps there is lens-to-lens variation? A problem with the coating on some of your elements during manufacture perhaps.

Looks like I have narrowed it down to these three although the Nikon may be out of reach ($750). So really between the Sigma and Tamron. If its a toss-up, the Sigma is a little cheaper.

Of course, it is not a toss-up--at least as far as the Nikon lens goes. You can't use the Nikon lens with your Canon camera.

Do a search and find test results on the Tamron and Sigma. I have a few Sigma lenses: 50-500 (aka Bigma), 70-300 APO, and 12-24 (aka Popeye). In my experience Sigma customer service has been excellent--far better than Canon's. My only Tamron is a 1.4x extender. It's OK, but is really a relabeled Kenko. A friend of mine uses the 18-200 Tamron and likes it just fine.

What you need is DXO Optics, it's a software upgrade for all your lenses - you won't need an L!

Seriously though, even without DXO I have never had a shot with significant CA from my 17-85, vignetting and distortion yes, but CA no. Perhaps there is lens-to-lens variation? A problem with the coating on some of your elements during manufacture perhaps.

I'll look into DXO. Seems like I read about that once before, and it was a fairly expensive program, although as you point out, a lot cheaper than new lenses.

My 17-85 seems consistent with the reviews and reports I've read. Users scream about the CA. The barrel and pincusion distortion is a bit of a throwback to the early days of zooms. I have not experienced the vignetting, though, even with a polarizer. I've read about sample variation in Canon lenses, but I've yet to find definitive proof--only claims on various forums ("I had to send back thennn lens three times before I got a good one").